The invention relates to burning fuel more specifically, to a fuel burning combustion head using a low-pressure, high flow atomizing nozzle so that there will be a complete combustion resulting in a minimum emission of pollutants.
For many years researchers have attempted to develop fuel burners which reduce emissions caused by unburned fuel. It has been discovered that a complete combustion of the fuel reduces emissions of pollutants particularly carbon monoxide, hydrocarbons, and soot. In burning liquid fuels, the problem is to provide sufficient oxygen for complete combustion of the carbon and hydrogen in the fuel to carbon dioxide and water, without high levels of excess air, which leads to reduced operating efficiency. This has led to an understanding that along with complete mixing, flame temperature and residence time affect the emissions levels released into the atmosphere. As a result burners have been developed with a longer residence time and a lower flame temperatures (blue flame). The prior art includes devices using fuel pressure atomizing recirculating burners (using no combustion air for atomization), high pressure air atomizing burners which use only a very small fraction of combustion air for atomization, and low pressure air atomizing burners which use a small percentage of the combustion air for atomization.
U.S. Pat. No. 2,531,538 discloses a fuel burner using pressurized fuel and having an air control unit that can control the amount of swirl in the air.
Another example is shown in U.S. Pat. No. 3,070,150, here the burner uses a low pressure, air atomizing nozzle however only a small fraction of the air is actually introduced through the atomizer. Most of the air is introduced in the combustion zone downstream through a complex series of ports.
U.S. Pat. Nos. 3,852,022 and 4,162,888 use oil pressure atomizing nozzles typical of all modem home oil burners. The combustion air in these burners is split into two parts; the first at the primary flame zone and the remainder to complete combustion.
U.S. Pat. No. 4,285,664 discloses a fuel oil burner using bluff bodies to generate turbulent wake flows. These wake flows help to mix the fuel and air and stabilize the flame. Only the fuel is pressurized and atomized for ignition.
U.S. Pat. No. 5,085,577, shows a pressurized fuel atomizing nozzle having a toroidal recirculating apportionment of air between the primary and secondary zones.
What is needed but not provided in the prior art is a fuel burner having the combination of a low pressure atomizing nozzle which uses all of the combustion air to atomize the fuel. The advantages of having this configuration would be the ability of the fuel burner to operate at low firing rates to more finely atomize the fuel, to premix the air and fuel sooner, eliminates the need for air compressors, eliminate the need for complex and costly flow baffles and channels to mix additional air and thus, creating a reduction in cost and complexity of the fuel burner. Finally, it would result in a lower electric power requirement, a cleaner burn, and a significant reduction in the release of pollutants.